Taxonomic Studies On 24 Species Of Viburnum In China

Viburnum L.belongs to the family Adoxaceae,mainly distributed in South America(temperate and subtropical regions)and Asia.Ca.200 species have been recorded in the world,and ca.73 species(45 endemic species),19 varieties and 2 forms were reported in China.As an important Chinese herbal medicine,it is characterized by clearing away heat and toxin,expelling wind and dampness,invigorating spleen and eliminating food,expelling insects,antitussive and expectorant,preserving health and anti-aging,with its roots,stems,leaves and mature fruits being used as medicine.In terms of morphological studies of 24 species(mainly belongs to sect.Odontotimus),observation of leaf epidermis morphology of 22 taxa(including 18 species,2 varieties and 2 formas)and palynology study of 7 representative species of Viburnum in China,we aim to provide a feasible taxonomic basis and basic research data for the taxonomic revision of the genus,and the main results as followed:(1)By observing and analyzing the morphological characters and variation patterns of24 species of Viburnum in China,we found that the number of lateral veins of leaves,glandular spots under leaves,inflorescence type,and corolla hairy coat are of great value in interspecific division.(2)In terms of the leaf epidermis micromorphology of 22 taxa(including varieties and formas)of domestic Viburnum,it was found that the epidermis cells on the leaves of Viburnum were irregular and polygonal;the vertical wall was mainly bow,shallow wave and wave;the shape of lower epidermis cells was irregular,and the vertical wall was mainly shallow wave,wave and deep wave.The stomatal apparatus is oval or nearly round in shape.Although the morphology of leaf epidermis cells varied in a few species,the variation range is stable,which can be used as the basis for identification and classification within species.The vertical wall pattern has a slightly obvious range difference between groups,which may be used as the auxiliary classification basis in different groups;due to the stable shape in species,the stomatal apparatus can be used as the basis for species identification and classification,with a certain taxonomic significance.(3)Comparing the observation results of palynology study of 7 species of Viburnum studies in the study with those previous study of the genus in China,we found the morphological variation range of pollen of sect.Odontotimus is somewhat larger than other groups.However,the morphological characteristics of pollen are of important identification value for the interspecific classification of the section.(4)The original and complete citation information of 88 taxa of Viburnum in China(species(including varieties and formas)were collated.Some of the incomplete original literature were supplemented and some source errors were corrected.(5)Type materials of 79 taxa of Viburnum genus(including varieties)in China were examined,of which 56 are holotype,129 are isotype,51 are syntype,353 are paratype,and130 are other type.Review of the original literature and traceability of type specimens are of great fundamental research value to the taxonomic revision of Viburnum in China.